WO2014070754A1 - Dispositif de combustion portable utilisant une génération thermoélectrique - Google Patents

Dispositif de combustion portable utilisant une génération thermoélectrique Download PDF

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Publication number
WO2014070754A1
WO2014070754A1 PCT/US2013/067284 US2013067284W WO2014070754A1 WO 2014070754 A1 WO2014070754 A1 WO 2014070754A1 US 2013067284 W US2013067284 W US 2013067284W WO 2014070754 A1 WO2014070754 A1 WO 2014070754A1
Authority
WO
WIPO (PCT)
Prior art keywords
teg
combustion
wall
set forth
combustion device
Prior art date
Application number
PCT/US2013/067284
Other languages
English (en)
Inventor
Jonathan N. CEDAR
Alexander H. Drummond
Clay Burns
Matthew Nowicki
Original Assignee
Biolite Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/662,650 external-priority patent/US8851062B2/en
Application filed by Biolite Llc filed Critical Biolite Llc
Publication of WO2014070754A1 publication Critical patent/WO2014070754A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00—Stoves or ranges
    • F24B1/26—Stoves with additional provisions for cooking
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00—Stoves or ranges
    • F24B1/02—Closed stoves
    • F24B1/022—Closed stoves easily collapsible or easily removable
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00—Stoves or ranges
    • F24B1/18—Stoves with open fires, e.g. fireplaces
    • F24B1/182—Stoves with open fires, e.g. fireplaces with additional provisions for cooking
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/10—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B40/00—Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Definitions

  • the present invention relates generally to combustion devices, such as fixed and portable cooking stoves, and more particularly to combustion arrangements that provide more efficient use of combustible materials and the energy generated therefrom.
  • portable combustion devices that may be used, for example, as a stove for cooking or heating, among other uses.
  • portable combustion devices required a variety of fuels such as those used for liquid fuel stoves, portable and fixed wood stoves and compressed gas fuel stoves. These stoves were used in a variety of different situations such as for camping, emergency or rescue situations, during a power outage or a similar scenario when traditional larger-scale cooking sources (for example gas/electric cooking rages and barbeque grilles) are not available.
  • traditional larger-scale cooking sources for example gas/electric cooking rages and barbeque grilles
  • the canister may not be thrown away like other types of trash, but need to be disposed in a special manner.
  • fuels, canister types, and portable combustion devices which are all made by different companies a person would be limited in their options and be forced to continue to use a single fuel source.
  • a biomass stove is able to burn a variety of biomass fuels such that a person would not be required to supply a compressed liquid fuel source for their portable combustion device. The user could employ whatever fuel is available to achieve the same combustion results as the previous devices. Additionally, the user need not dispose of potentially toxic canisters, and he or she would not be required to carry the appliance's fuel source with him or her. Also, whatever fuel is unused can simply be left behind.
  • biomass combustion or biomass stove burning wood chips, twigs, leaves, peat, etc. (or low-grade coal in some instances) is often used as the primary cooking device for the family meal.
  • biomass combustion is carried out in some form of simple fire-driven stove, which is used for both heating and cooking.
  • biomass devices typically have drawbacks that render them undesirable in many situations.
  • biomass stoves are not "clean" burning, that is they produce soot and smoke during the combustion process, which can cover pots, pans, or even food during the combustion.
  • the smoke generated during the combustion process can make the biomass stoves potentially dangerous for indoor use— as the smoke contains large quantities of soot and other toxic combustion products, including carbon monoxide. Nevertheless, such stoves are often used in small indoor spaces with inadequate ventilation in developing countries.
  • biomass stoves are heavy or built-in, making them less suitable for field use, as they are not easily portable.
  • One technique for increasing the efficiency of combustion is to provide a driven airflow through the biomass with a powered fan, using a variety of motive power sources including, but not limited to, spring and clockwork mechanisms, compressed air/gas and electricity.
  • the fan is typically driven by a battery or other electrical source.
  • batteries may have a short life in use, and/or be discharged (dead), or be in need of recharging, when needed.
  • batteries are expensive and often unavailable to peoples of developing countries.
  • batteries are environmentally unfriendly and often disposed of improperly.
  • a portable combustion device that is capable of being used as a stove for cooking and/or heating, which burns commonly available wood and other biomass, and provides similar heat output as other liquid or gas fuels, without the need for batteries or disposable/refillable canisters of fuel.
  • the stove can desirably be easy to carry, low-maintenance and burn fuel without exhausting significant soot, smoke or toxic combustion byproducts.
  • the stove can desirably employ inexpensive and commercially available components and conventional construction techniques in its manufacture.
  • This invention overcomes disadvantages of the prior art by providing a portable combustion device that provides a cleaner combustion, reduces the kindling period, and provides a more efficient overall combustion through the use of a fan that directs a predetermined volume of airflow over the combustible fuel— typically wood or similar cellulose-based biological solids.
  • the direction of airflow is accomplished without the need for canister fuels or external power sources using the stove's own generated heat with the aid of a thermoelectric generator (TEG) and novel heat sink arrangement to generate electricity that powers the fan, and drives the airflow.
  • TOG thermoelectric generator
  • the combustion device has a combustion chamber into which the fuel source is placed for combustion.
  • a housing mounted to the wall (for example along a side) of the combustion chamber is a housing that encloses the TEG, which generates an electrical output based on a difference in temperature on opposing sides (a "hot side” and a "cold side") of the thermoelectric device, wherein the larger the differential, the larger the electrical output.
  • a heat-conducting probe and heat-conducting probe base unit Mounted onto the TEG housing and protruding into the combustion chamber through a small passageway.
  • the heat-conducting probe is constructed from a material capable of efficiently transferring the heat generated in the combustion chamber to the heat-conducting probe base, which is in contact with the hot side of the TEG device.
  • the TEG is also in contact with a heat sink having a plurality of independent vanes extending from the base, which is designed to remove heat from the TEG device through interaction with ambient air that passes over the vanes from a port located along the side of the TEG housing.
  • the TEG housing has a motor and a airflow driver in the form of a fan (for example an axial centrifugal fan that employs moving blades, vanes or the like to drive air) near the heat sink to further draw air away from the heat sink and/or blow ambient air through the heat sink into the combustion chamber (depending in part upon where the airflow driver(s) is/are located with respect to the heat sink) and aid in the cooling of the heat sink, and to force air onto the combusting fuel through a plurality of peripheral ports that connect with an air space located between the inner and outer walls of the combustion chamber.
  • a fan for example an axial centrifugal fan that employs moving blades, vanes or the like to drive air
  • This arrangement thereby affords the fan-driven airflow the dual purpose of cooling the cold side of the TEG to create a higher heat differential between it and the hot side of the probe and oxidizing the burning fuel, while also insulating the TEG housing from the hot inner walls of the inner flame-contacting part of the combustion chamber.
  • the airflow driver draws or blows outside air into the TEG housing to further cool down the heat sink by drawing cooler outside air across it, as well as drawing the air near the heat sink away from the heat sink. This will cool one side of the TEG device creating a larger temperature differential, which will increase the electrical output to drive motor and fan structure, which will continue to draw more into the TEG housing.
  • any surplus electricity from the TEG can be used as part of a cogeneration system to power a charging system for a variety of electrical or electronic devices having appropriate power consumption levels relative to the available heat energy.
  • Such devices can include, for example a radio, light or cellphone charger.
  • one or more connectors can be provided to the TEG assembly and/or housing that employ a common standard, such as 12 VDC or USB.
  • the airflow driver draws or blows the ambient air from the heat sink and forces the air into the combustion chamber creating more turbulence within the chamber insuring a more efficient combustion. All of these components provide a system that promotes a portable or stationary combustion device which is capable of using biomass fuels that does not require canisters or an external power supply.
  • the invention thereby provides a cleaner burning of biomass fuels, and the use of the TEG device in this configuration ensures a quicker kindling period as well as more efficient combustion. More particularly, the placement of the TEG and its heat-conducting probe, so as to receive optimized heat transfer from the flame and thereby more quickly heat the TEG, ensures quicker operation of the fan/airflow driver, and obviates the need for a startup battery.
  • the heat conducting probe defines a conduit for conducting heat from a remote flame or heat source.
  • This discrete heat conduit enables a variety of many flexible design configurations where the TEG and airflow driver can be placed on the outside surface or remotely from (and typically near) any combustion device such as biomass stoves, barbeques, grills, camp fires, butane, alcohol and propane burners, and any other source of open flame and/or heat convection (for example a heated airflow).
  • the combustion device includes a combustion chamber comprising an inner wall defining a combustion space that contains, and is in communication with, a biomass fuel source. There is also provided an outer wall having a side-mounted interface port allowing access to an airspace between the inner wall and the outer wall, the inner wall further comprising a plurality of ports located about the perimeter of the inner wall and providing access to the combustion space.
  • a TEG is located outside the outer wall and including a thermally connected heat-conducting probe on a hot side thereof that extends into the combustion space.
  • the TEG further includes a heat sink thermally connected to a cold side thereof.
  • a motorized airflow driver is electrically connected to the TEG, and is arranged to draw air form an ambient source, over the heat sink and into the interface port so as to generate a positive pressure in the airspace and direct airflow through the plurality of ports and into the combustion space.
  • the inner wall illustratively includes a lower and upper set of peripheral ports that allow the airflow that is driven into the space between the chamber walls to be injected into the interior of the chamber to mix with the burning fuel therein.
  • a deflector is positioned in front of the port in the outer wall to direct the flow of air into a circular pattern, thus creating improved mixture of air and combustion gas, and generating a more-distributed flow within the space.
  • the device includes a set of three legs that elevate the device bottom over a supporting surface.
  • the TEG housing is shaped as a semi-cylinder, sized to be inserted through the top of the combustion chamber for storage therein.
  • the TEG housing can be provided with a predetermined or variable length heat-conducting probe and an extended or differing-shape interface pipe to allow attachment to a variety of combustion devices, such as a barbeque grille or wood burning stove.
  • a variety of combustion devices such as a barbeque grille or wood burning stove.
  • Appropriate mounting mechanisms can be employed to facilitate mounting of the TEG unit of this universal embodiment to a combustion device.
  • a combustion device in the form of a cook stove having a side-fed combustion chamber is provided.
  • This stove can be adapted for more regular use by a person or family (for example) in remote regions or those lacking utilities.
  • the device/stove provides a combustion chamber having an upper region and a lower region.
  • the lower region includes a side fuel entrance port near its base.
  • An upper region extends from the lower region to a top end.
  • the upper region includes an inner wall defining a combustion space that contains, and is in communication with, a biomass fuel source.
  • the upper region also includes an outer wall having a side-mounted interface port allowing access of airflow into the combustion space enclosed within the outer wall.
  • the upper region of the combustion space includes an outlet at its top end thereof for escape of combustion gasses and application of heat to an object.
  • a thermoelectric generator (TEG) is located outside the outer wall, and includes at least one thermally connected heat-conducting probe on a hot side thereof that extends into the combustion space.
  • the TEG also includes a heat sink thermally connected to a cold side thereof.
  • a motorized airflow driver (e.g. a fan) is electrically connected to the TEG and is constructed and arranged to drive air from an ambient source, over the heat sink and into the interface port so as to generate a positive pressure in the combustion space.
  • the port structure that provides airflow from the TEG assembly to the upper region includes a plurality of air- injection ports distributed around the inner wall.
  • the air injection ports are located around a perimeter of an upper portion of the upper region at a first spacing therebetween.
  • the injection ports are located at positions on the upper region beneath the upper portion at a second spacing therebetween that is greater than the first spacing.
  • the air injection ports are more densely provided near (adjacent to) the top and less densely provided near (adjacent to) the bottom of the upper region.
  • the device/stove can particularly include a side fuel feed opening located at the bottom side of the combustion space.
  • a fuel crib is located at least partially within, and partially external to, the combustion space.
  • the fuel crib is constructed and arranged to allow air to flow beneath and above fuel located thereon for more complete combustion.
  • the fuel crib can define a lattice, grille or perforated panel, which includes a heat deflector plate (that is generally unperforated, unlike the open lattice). This plate can be located below the fuel in the area of the side fuel feed opening.
  • the device/stove can define a base with an associated outer shell extending upwardly from the base, and a widened cooking top extending upwardly from a narrowed region of the outer shell. These components collectively define, in side view, the shape of an hourglass.
  • the outer shell can include fixed (or movable) handles that extend outwardly from a narrowed region of the outer shell.
  • the handles extend outwardly to a location that is approximately equal to or less than a maximum perimeter of the combustion device to provide core compact perimeter that is less likely to interfere with a the cooking process.
  • a circuit assembly provides electricity from the TEG to at least one connector constructed and arranged to electrically connect an electronic or electrical device.
  • the connector(s) can be adapted to deliver electricity according to a common standard, such as 12 VDC and/or USB.
  • Fig. 1 is a perspective view of a portable combustion device, according to an illustrative embodiment of this invention, showing the combustion chamber and TEG housing fully assembled;
  • Fig. 2 is side view of the portable combustion device of Fig. 1 according to an illustrative embodiment of this invention
  • Fig. 3 is a top view of the portable combustion device of Fig. 1 according to an illustrative embodiment of this invention
  • Fig. 4 is a perspective view of the TEG housing according to an illustrative embodiment of this invention.
  • Fig. 5 is a side cross-section of the TEG housing according to an illustrative embodiment of this invention, taken along line 5-5 of Fig. 4;
  • Fig. 6 is a side cross-section of the portable combustion device of Fig. 1 according to an illustrative embodiment of this invention, taken along line 6-6 of Fig. 3;
  • Fig. 6A is a partial top cross section of the combustion chamber illustrating airflow therethrough;
  • Fig. 7 is a perspective view of the heat sink for use with the TEG according to an illustrative embodiment of this invention.
  • Fig. 8 is an exploded perspective view of the TEG housing, as contained within the combustion chamber showing the disassembly and folding of the device for storage, wherein the legs of the portable combustion device are shown in the collapsed position, and the TEG housing is directed into the body of the device, according to an illustrative embodiment of this invention;
  • Fig. 9 is a partial side cross section of a universal application of a TEG unit in accordance with an embodiment of this invention, used to improve combustion in an exemplary combustion chamber— in this example a barbeque grille or wood-burning stove;
  • Fig. 10 is a perspective view of an exemplary side-fed "rocket" stove employing a TEG unit in accordance with an embodiment of this invention, in which the TEG unit includes a cogeneration circuit for powering a variety of electronic and/or electrical devices;
  • Fig. 11 is a generalized schematic diagram of the TEG unit power circuitry according to an embodiment that includes a cogeneration circuit and power storage capabilities;
  • Fig. 12 is a perspective view of a combustion device, according to a further embodiment, in the form of a cooking stove with a side-fed fuel opening having an illustrative fuel support crib associated therewith; and
  • Fig. 13 is a side cross section of the combustion device taken along line 13-13 of Fig. 12, further detailing its internal construction, which includes illustrative air injection ports.
  • biomass fuel can be taken broadly to include any fuel, coal, oil, waste products, etc, that will burn more cleanly and efficiently by injection of air during combustion.
  • biomass can be taken broadly to include any fuel, coal, oil, waste products, etc, that will burn more cleanly and efficiently by injection of air during combustion.
  • a further advantage of increased efficiency in the burning of fuel is that less fuel is consumed for a given heat output.
  • Figs. 1-3 show various views of the portable combustion device 100 according to an illustrative embodiment of this invention.
  • the depicted portable combustion device 100 is relatively cylindrical in shape and is comprised of an internal combustion or burn chamber 102 and a TEG (thermoelectric generator) housing 1 10 constructed of a durable polymer or lightweight metal, such as an aluminum casting.
  • the combustion chamber 102 is preferably made of a lightweight, durable metal, capable of withstanding the high temperature of combustion with an open flame.
  • the depicted portable combustion device 100 is constructed from steel (e.g. stainless steel sheet having a thickness of 1/32-1/16 inch, variously) and aluminum sheet, with polymeric components where appropriate.
  • the combustion chamber can be any other material (or combination of materials) that is durable and capable of with standing high temperatures.
  • the shape of the combustion chamber is variable and may be any perimeter and three-dimensional shape, so long as it provides an adequate chamber for combustion of fuels. In this embodiment, it is a cylinder with an inner and outer wall structure providing an airspace therebetween.
  • the combustion chamber can be a more basic enclosure in which the fuel is enclosed to create a flame and allows for injection of air thereinto in accordance with this invention (described below with reference to a "universal" TEG device).
  • the combustion chamber 102 may be disposed within an outer, perforated heat shield 104.
  • the heat shield provides a small barrier to protect against the high temperature within the combustion chamber 102 and is separated from the combustion chamber 102 by an air space 109 that is between approximately 1/8 and 1 ⁇ 4 inch in radius in this embodiment.
  • the rear side 11 1 of the heat shield 104 is flattened to receive the TEG housing 1 10 and is secured to the combustion chamber by rivets or other fasteners at the rear.
  • the perforations 1 13 are formed into bent-over stand-offs (320, shown in top view in Fig. 3) attached to one edge of each perforation that maintain the spacing between the heat shield 104 and the combustion chamber 102 without conducting substantial quantities of heat.
  • heat shield 104 can be employed between the heat shield 104 and combustion chamber 102.
  • the illustrative heat shield 104 is constructed from relatively thin-gauge stainless steel as well. However, in an alternate embodiment other durable materials, such as aluminum or a composite, can be employed. Also, while depicted with perforations 113, the heat shield 104 need not be perforated, as it may be a single unitary piece. The heat shield may also, in the alternative, be omitted entirely. In a still further embodiment, the heat shield 104 may be a modular design such that it may be removably secured to the portable combustion device 100.
  • a vertical, pot support or standoff 108 is disposed on a top edge of the combustion chamber 102.
  • the standoff 108 is secured to the top edge by sandwiching between an outer and inner portion of the combustion chamber that are joined at the top.
  • the standoff 108 is formed from a stamped or cut piece of stainless steel sheet.
  • the standoff includes a set of peripheral wings 122 that are shown bent upwardly from a common annular base (see annular base 650 in Fig. 6), which is sandwiched between the inner and outer portions of the combustion chamber.
  • the wings 122 are spot-welded (or otherwise joined together) to form the repeating pattern of curvilinear segments about the perimeter of the combustion device's top end.
  • the wings 122 when joined together into a somewhat frustoconical, upward-outwardly expanding shape, define lower air vents 124 and upper air vents 126 with respect to a pot placed thereupon.
  • the standoff 108 provides a level surface for placing an item, such as a pot or pan, to be heated during operation of the portable combustion device 100.
  • the standoff 108 is generally constructed to maintain the flame within the combustion chamber 102 directed towards the center of the opening at the top of the combustion chamber 102. This lessens the amount of flame that escapes from the combustion chamber 102 and allows more oxygen to flow to the fire, thereby providing for more efficient combustion.
  • the standoff 108 is constructed from stainless steel.
  • the standoff 108 can be constructed of any material capable of withstanding the high temperatures of combustion supporting a weighted cooking vessel, and formed into the correct shape as required. Such temperatures can be in the range of 1200-1600 degrees F.
  • the standoff 108 is of a modular design such that it capable of being added or removed with fasteners or clips. Likewise, it can be formed from a unitary casting in other embodiments. In still other embodiments, the standoff can be constructed as a cast or bent wire, having a high temperature resistance without deforming.
  • the portable combustion device 100 may also have secured to the heat shield or outermost wall 104 (with screws passing into the outer combustion chamber 102) a plurality of legs 106, 107 to provide a sturdy, stable base for the combustion chamber 102.
  • the legs 106, 107 are collapsible on their bases 130, 134, such they provide for easy storage and transportation of the device when not in use.
  • two legs 106 fold pivotally about transverse pivots 132 (see Fig. 8) beneath the bottom of the combustion device.
  • the rear leg 107 conversely, does not fold under the combustion device, but rather rotates (see double curved arrow 820 in Fig.
  • the legs 106 are constructed from a durable plastic polymer. However any materials known in the art such as metals, rubbers, composites, or similarly durable materials can be utilized as well.
  • the TEG housing 110 is fully independent of, and remote from the legs, all legs can be adapted to collapse beneath the device and an alternate structure can be used to support and secure the TEG housing 1 10 in place on the side of the device.
  • the slotted ventilation system 112 comprises a series of slots (or any other acceptable porting arrangement) within an upper portion of the outwardly - disposed sidewall 150 of the TEG housing 1 10. These slots allow air from the ambient environment to be drawn into the TEG housing 1 10 to promote efficient combustion of the biomass fuel contained within the combustion chamber.
  • the TEG housing as depicted is essentially a semi-cylinder with a cylindrically curved wall 150 facing outwardly when attached to the combustion chamber 102.
  • the inner wall 230 is flattened to confront the flattened rear wall 1 11 of the combustion chamber 102.
  • the approximate height 216 of the combustion chamber 102 in an exemplary embodiment is in a range of 5-8 inches.
  • the overall diameter 218 of the combustion chamber 102 is in a range of approximately 4-6 inches.
  • the exemplary diameter 218 of the heat shield 104 is approximately 4.5-6.5 inches.
  • the TEG housing height 210 is approximately 4-6 inches and the radius 212 of the TEG housing is approximately 2-3 inches. It should be clear that the dimensions provided herein are exemplary of a device of a given device size and that the relative sizes of components can be varied where a larger or smaller combustion device is desired.
  • the size and output of the TEG and airflow driver can be varied to suit the particular application.
  • the TEG can be of larger size/output, or multiple TEG units can be used in parallel, or in series.
  • the depicted embodiment provides a single combustion chamber 102 for the overall device 100, it is expressly contemplated that the device can include a plurality of individual combustion chambers with respective standoffs for receiving individual cooking implements, etc.
  • each burner can be serviced by an interconnected TEG system that provides forced air throughout the burner group at all times, or by individual TEG units that are independently operated based upon the heat present in that particular burner.
  • each burner in either a single or multiple-burner device
  • a top view of the portable combustion device 100 of the illustrative embodiment is shown.
  • the combustion chamber 102 is disposed within, and surrounded by, a heat shield 104.
  • the legs 106 extend outwardly from the portable combustion device so as to provide a sturdy base.
  • the legs are shown in the extended position in Fig. 3, as compared to the collapsed position, as shown in Fig. 8.
  • the heat-conducting probe 404 (shown more clearly in Fig. 4) has a thermally conductive base 406 secured to the TEG housing 1 10.
  • the heat-conducting probe 404 is in thermal communication with the TEG and provides a probe that extends into the combustion area, protruding through a port in the in walls of the combustion chamber 102. This heat-conducting probe 404, as will be described in greater detail below, allows for greater transmission of heat from the combustion area to the TEG as it intercepts the flames created by the combustion.
  • the TEG housing 110 is removably coupled to the side of the combustion chamber 102 by the upwardly angled heat-conducting probe 404 combined with a support base 408 at the bottom of the TEG housing.
  • the angle A of the heat-conducting probe is approximately 20- 40 degrees with respect to the horizontal 410 in this embodiment. The angle is highly variable, but should allow the pipe 404 to be readily passed into and out of conforming holes in the combustion chamber 102.
  • the angle of the probe can be steeper that that required to readily pass it into or out of the chamber, although it is expressly contemplated that the angle of the probe in this embodiment and others described herein is widely variable.
  • the angle of the heat conducting probe can be defined so that the probe extends parallel, but attached to, the surface of the hot side heat sink.
  • the TEG unit can be an integral section of the combustion chamber, and can be removed with that section of the chamber itself.
  • Such permanent or semi-permanent fixing can be achieved by forming the TEG housing integrally or unitarily with the associated combustion device or applying it to a wall of the device using fasteners (e.g. rivets or screws) that do not lend themselves to rapid removal by only a few movements and/or without tools.
  • the wall 230 of the TEG housing is brought into a confronting relationship with the rear wall 1 11 of the combustion chamber and the TEG support base 408 rests upon the support surface 232 of the leg base 134.
  • the upper tip 240 of the leg 107 interferes with removal of the support base 408 with respect to the surface 232.
  • the angled geometry of the heat-conducting probe 404 resists movement of the TEG housing 110 away from the rear wall 1 11 of the combustion chamber 102 when the tip 240 locks down the base 408. As shown in Fig.
  • the leg 107 includes a live spring lever 620 that can be biased inwardly (arrow 622) to enable the leg to be unlocked with respect to its base 134 and pivot (double curved arrow 820 in Fig. 8) about the bolt/pivot 140 to move the leg's upper tip 240 out of interfering contact with the TEG support base 408.
  • the angled geometry of the probe also allows it to be placed so as to take best advantage of the heat generated during the kindling stage so as to expedite startup of the airflow driver. Likewise, the placement also allows for the good ongoing transmission of heat from the top/cone of the flame after the kindling stage.
  • the length of the probe is highly variable so as to locate it within the hot region of the fire.
  • the heat conducting probe can be positioned at the outlet or rim from where the flame leaves the stove.
  • the probe can be shaped as a hook so as to depend from the rim of the stove or fire enclosure, with a portion of the hook projecting into the fire enclosure. In this manner the TEG assembly is removable by unhooking and lifting it away from the rim or other enclosure edge. It is engaged in the reverse fashion— by hooking it to the rim or edge when needed.
  • the illustrative TEG housing 1 10 is a modular design capable of being removably engaged with the combustion chamber 102.
  • the TEG housing and combustion chamber 102 may be a single integrated device.
  • the TEG housing 1 10 may be secured to the combustion chamber 102 with clips, fasteners or other devices known in the art for securing objects together.
  • the TEG unit (or units) can be located remote from the combustion chamber and device wall, being connected mainly by an appropriately sized heat-conducting probe and an air conduit in communication with the airflow driver so as to deliver a stream of air from a remote location. Such an arrangement is described by way of example with reference to Fig. 9 below.
  • the airflow interface 402 When the TEG housing 110 is securely locked in place against the wall, the airflow interface 402, which is located in the bottom rear of the TEG along wall 230, is in engagement with an air port formed in the combustion chamber.
  • the airflow interface 402 may include a heat-resistant gasket (constructed from silicone, for example) 430 to form a seal between the TEG housing 1 10 and the combustion chamber 102 in the region of the air port (see port 830 in Fig. 8 with TEG removed).
  • the port 830 is sized and arranged so that the gasket 430 completely surrounds and seals it against leakage.
  • the seal between the TEG and the combustion chamber can be constructed from any durable material capable of withstanding elevated temperatures and providing a sufficient seal between two components.
  • the heat-conducting probe 404 is secured to the TEG housing 110 at the thermally conductive heat-conducting probe base 406, which is in direct, thermally transmitting contact with the "hot side" of a TEG device 508.
  • the heat-conducting probe 404 can be a hollow tube, having an outer diameter DHP of approximately 1/8-3/8 inches in this embodiment, and can be constructed from any acceptable heat-conducting material, such as steel, copper, graphite or aluminum.
  • the probe can be partially or completely solid in alternate embodiments and can have any cross sectional shape that does not substantially interfere with transmission of heat to the top opening of the chamber 102, and otherwise allows transmission of heat in sufficient level to the hot side of the TEG 508.
  • the heat-conducting probe base 406 can be a cast or milled material that is also any acceptable material, such as steel, aluminum, graphite or copper.
  • the heat conducting probe can be formed to extend at any appropriate angle and shape such as, but not exclusively, an arc or "s" curve.
  • the base 406 is shaped as a rectangular plate in this embodiment, with an exemplary thickness of 1/16- 5/16 inch.
  • the heat-conducting probe 404 is attached to the base 406, for example, by brazing or welding.
  • the base 406 is adhered to the TEG 508 by heat-conducting adhesives and/or peripheral fasteners.
  • the make, model and performance specifications of the particular TEG or TEGs (where an array of two or more TEGs is used) employed in an embodiment can vary significantly depending upon power requirements, size and cost, among other factors.
  • the TEG is constructed and arranged to generate 0.2 - 2.0 watts and 1.0 - 3.0 volts at a temperature differential of ⁇ 100 - 200 degrees F. Larger-output TEGs can be employed for cogeneration (described further below), or for use in powering more inefficient motors.
  • TEG for the illustrative application
  • FF-N20PN that draws approximately 0.135 Amps at 1.5 volts.
  • Another exemplary TEG for an illustrative application is available from Marlow Industries, Inc. of Dallas, TX as model TG 12-4-01L, having a power output of 0.5 - 1.0 watts, 1.5 - 2.0 volts, with a heat differential of approximately 120 degrees Fahrenheit.
  • Yet another example from Laird Technologies of Trenton, NJ is the model HT4-12-F2-3030- TA W6 having a power output of 1.4 watts, 1.7 volts, with heat differential of approx. 120 degrees F.
  • a higher output level for example up to 10 watts can be appropriate).
  • Increased power output can also be achieved by using multiple TEGs as noted above.
  • the TEG is selected for high-hot-side temperature applications due to its exposure to the flame of the combustion chamber.
  • a lower-temperature TEG can be employed.
  • High-temperature TEGs are typically assembled using a high-temperature solder and/or similar attachment mechanism.
  • "cold side" of the TEG device 508 is a heat sink 502.
  • Mounted below the heat sink 502 in the TEG housing 110 is an electrically driven motor 506 of appropriate voltage to be compatible with the TEG.
  • the motor 506 rotates to drive a fan, illustratively shown as a centrifugal impeller 504, in a direct-drive implementation.
  • the impeller defines upright, angled fins mounted to a base.
  • any acceptable fan arrangement can be employed including a radially, directed propeller-style blade set joined to a common hub.
  • the terms "airflow driver” and “fan” should be taken broadly to include any acceptable driven, air-mo ving/driving structure or device.
  • the illustrative embodiment employs a drive motor for the fan that operates from approximately 1.5 volts to 6 volts DC, and has a start-up voltage of 2/10 volt. Such a motor is generally suitable for operating the airflow driver in a stove of the depicted size and heat capacity.
  • the size and power-handling of the motor as well as the size and airflow of the fan are highly variable.
  • the fan and motor can be varied to suit a differing TEG output and/or where multiple TEG/airflow driver assemblies are employed.
  • the impeller 504 is made of a durable plastic.
  • the fan 504 can be made of other materials, such as steel, aluminum or any material known in the art used for making reliable, efficient, and lightweight fan structures.
  • the placement of the fan or other airflow-driving mechanism with respect to the TEG and its heat sink is highly variable.
  • the airflow-driver can be positioned upstream of the heat sink to blow air over it.
  • one or more motors or other driving devices can be arranged to both pull (as shown) and blow airflow with respect to the heat sink.
  • the term "draw” should thus be taken broadly to embody any of these airflow-driving arrangements.
  • the wiring and circuitry used to connect the TEG and motor have been omitted in the drawing for clarity.
  • the electrical connections and associated control circuitry can be implemented in accordance with well-known electronic principles.
  • the circuit can include current limiters and other functional components that improve the performance of the system and avoid damage to the motor due to an under- voltage or over- voltage condition.
  • additional circuitry can be provided to facilitate startup at low voltages, during the kindling stage.
  • the wiring can interface with a control circuit that includes a speed control (for example a potentiometer or pulse width modulator) that allows the user to vary the fan speed. This could be beneficial where the user desires to raise or lower the heat output of the fire.
  • the unit can include an optional small rechargeable or disposable battery and/or storage capacitor that assists in providing initial power to the airflow driver (at the direction of an "on" switch) at the initiation of the kindling stage, before sufficient heat is built up. More generally for power storage is useful in supporting various cogeneration arrangements as described further below by ensuring that the output of power is always sufficient to support the connected device's(s') needs. Whenever TEG output attains a predetermined output level in excess of draw by the device and/or fan motor, the system's control circuitry engages a charging circuit of conventional design, which replaces the battery's or capacitor's spent energy.
  • the flattened wall 230 of the TEG housing 110 is removable from the remaining housing for service and initial assembly.
  • the wall 230 is attached to the remaining housing using a variety of techniques including fasteners, such as machine screws or self-tapping screws.
  • the heat sink 502 comprises a plurality of parallel vanes 720, 722 and 724 that project outwardly from a common planar base 726.
  • the vanes can be sized and shaped in a variety of ways. In this example, they each define a horizontal spacing with respect to each other of approximately 1/8-1/4 inch and a vertical spacing 730 of approximately 1/16-1/8 inch.
  • Each vane has a vertical height 740 of between 3/16 and 5/16 inch and a horizontal width of between 1/16 and 3/16 inch.
  • the heat sink 502 can be constructed from any acceptable thermally-conductive material, such as aluminum, cooper, iron, steel, graphite, and the like, using any acceptable manufacturing technique, such as casting and/or machining.
  • the base 726 of the heat sink 502 is mounted in direct thermal contact with the cold side of the TEG 508 using fasteners, adhesives and/or another acceptable technique.
  • the combustion chamber 102 is divided into an outer wall or shell 670 having sides and a bottom 672, and an inner wall 674 also having sides and a bottom 676.
  • Each set of walls 670, 672, 674, 676 defines a "pot" shape with a closed bottom and open top.
  • the inner pot defines a combustion space that receives the biomass fuel (not shown) for burning therein.
  • the walls 670, 647 join at a top annular junction 690. The junction is formed by folding in the outer walls 670 so that they form a receiving orifice that is sized to snugly fit the outer diameter of the inner wall structure 674. As shown, the top joint between the inner and outer walls sandwiches the annular base ring 650 of the standoff 108.
  • the space 678 between the walls 670, 674 and bottoms 672, 676 receives a positive pressure from the airflow induced by the TEG.
  • the flow is enhanced by a deflector 680 placed in front of the combustion chamber port 830.
  • the deflector 680 is secured to the wall 670 by an angled side base 682 as shown in Fig 6A, so that airflow does not become concentrated on one part of the inner wall 674, but rather is allowed to escape the open side 684, and thereby circulate (arrows 686) throughout the space 678.
  • This circular flow helps to better distribute the air generated by the impeller and better mix the air and combustion gasses within the combustion space.
  • the deflector ensures that radiant heat from the combustion chamber is not projected back into the TEG housing.
  • the airflow within the space is distributed into the inner space of the walls 674 and bottom 676 is directed inwardly (arrows 612) at two discrete sets of peripheral ports 602 and 604, located respectively adjacent to the top and the bottom of the inner wall structure 674.
  • two rows of 1/8 to 1/4-inch ports (602) are provided approximately 1-2 inches from the top edge of the combustion chamber 102, and a single row of 1/8-1/4-inch of ports (604).
  • the number of air ports, their placement and shape are highly variable.
  • the ports are sized and placed so as to provide an effective mechanism for directing airflow through the enclosed burning fuel without the risk of becoming clogged by the fuel or ash debris.
  • the port placement better ensures overall oxidation of the fuel.
  • a single, enlarged port can be employed, or a conduit (air pipe) that directs airflow, via an outlet, to a desired location within the chamber can be employed.
  • the inner walls 674 and bottom 676 are constructed from a unitary-stamped, or built-up/welded-together construction of stainless steel, and the outer walls 670 and bottom 672 are constructed from sheet aluminum that is formed into the illustrated "pot" shape.
  • ambient air is drawn through the slotted air vent 112 (arrow 560), and into the TEG housing 1 10 as shown.
  • the ambient air is used to cool the heat sink 502 and draw heat away from the heat sink 502 to promote a more efficient cooling of the TEG device 508, thereby creating a greater temperature differential with respect to the TEG hot side and interconnected heat-conducting probe 404.
  • additional outside air can also be drawn in through the lower air vent 204 in the housing 110.
  • the flow of air through this vent 204 is controlled by a rotating baffle or draft 208.
  • the airflow from the baffle or draft also serve to cool the heat sink 502, as it rises through the housing 1 10 (shown by arrow 610).
  • the baffle 208 can be closed although this may not be required in alternate embodiments.
  • a baffle or draft could be used to adjust the amount of air entering the burn chamber and generally isolate the airflow circuit from the slots 1 12 to the airflow interface 402 (and combustion chamber port 830).
  • the baffle or draft 208, or vent 204 need not be closable and/or adjustable. It can alternatively define an open draft vent. In this manner, excess pressure from the airflow driver can be exhausted through it.
  • the vent 204 can be configured by way of specifically sized and shaped baffles or draft or a venturi— in accordance with accepted aerodynamic principles— to maintain air flow into the chamber combustion chamber via the lower vent.
  • the placement of the TEG housing on the outer wall 11 1 of the outer combustion chamber wall structure 670, combined with the airspace 678 between the inner combustion chamber walls 674 and outer walls 670 helps to ensure that the TEG housing remains relatively thermally isolated, except for the TEG itself through the length of the heat probe. Hence, the interior of the housing is not significantly heated by heat conducted or radiated from other parts of the combustion chamber. In other words, the airflow can be focused on carrying heat away from the TEG via the heat sink. Without the insulating air cushion provided by the airspace 678, the housing would tend to heat up more generally due to conduction and radiation from the burning fuel in the adjacent combustion chamber.
  • the location of the heat-conducting probe 404 provides for the warmest air (typically near the cone of the flame) to be transferred to the heat- conducting probe base 406, thereby efficiently creating the best temperature differential in the TEG.
  • the advantageous heat-conducting probe placement that this enables.
  • this positioning is nearest to the kindling stage of the combustion so as to enable quick and efficient start-up of the TEG unit.
  • the use of the novel heat- conducting probe of the illustrative embodiment also allows for a smaller-output TEG device, thereby reducing unit cost and saving space, as more energy is concentrated at the device during operation.
  • the probe and/or airflow outlet can be located at other positions on the combustion chamber that provide other benefits to the combustion device and its operation.
  • the illustrative embodiment of the combustion device 100 is particularly adapted for compact portability in a pack, bag or other small-volume container.
  • the TEG hosing 1 10 has an overall diameter 850 at its curved side 150 that is less than or equal to the outer diameter 852 of the inner wall 674 of the combustion chamber 102.
  • the TEG housing 1 10 can be inserted (arrows 854) into the combustion chamber 102, so as to provide a more compact profile.
  • the top side 860 of the housing 110 includes a lip 862 that extends beyond the diameter 850 to prevent the housing from falling into the chamber, and to allow easy withdrawal of the housing when needed.
  • This lip 862 also helps to prevent accidental spills from entering the TEG housing 110 and potentially clogging or damaging the internals.
  • the remaining space within the inner combustion chamber is available for storage of a small amount of fuel or other items.
  • the legs 106 and 107 have also been folded (double curved arrows 820, 870) about their respective pivots 132, 140 to provide the desired lowered profile for ease of transport. In this folded state, the leg 107 also acts to unlock the TEG housing 110, as described above.
  • the illustrative embodiment of the present invention provides a device having a shorter, more-efficient kindling period, as well as substantially more-efficient overall combustion.
  • the use of the conventional biomass-type fuels eliminates the need for purchasing, carrying, and disposing of potentially toxic fuel sources.
  • the TEG device 508 eliminates the need for batteries or other external power sources to drive or start the airflow driver that is used to promote the more efficient combustion process.
  • the novel placement and arrangement of airflow-generating and delivery structures also increases the efficiency of the device.
  • the above-described invention generally provides an apparatus and method that is capable of being used in a wide variety of situations, from camping, emergency situations, or used in a developing country as a primary heat and/or cooking source.
  • the principle of the TEG unit as contemplated herein can be applied to a variety of more conventional combustion devices. More generally, the TEG housing 1 10 described above can be adapted to interoperate with any device having an enclosed combustion chamber, even those with a single wall, provided that the TEG housing (or a modified version thereof) is sufficiently isolated from heat to prevent damage to its external or internal components. Moreover, even burning arrangements that are essentially exposed to the environment, such as a three-stone fire, "rocket" stove, and the like, may benefit from the TEG device of this invention, by increasing airflow onto the burning fuel to increase efficiency and reduce smoke emissions (described below). Thus, Fig.
  • FIG. 9 shows a partial side cross section of a combustion device arrangement 900— in this example comprising a substantially conventional single-wall enclosed combustion pot or kettle 902— as the exemplary combustion chamber that can be used in conjunction with a TEG device 910, according to an embodiment of this invention.
  • a combustion device is a charcoal burning stove or barbeque— however any combustion device may benefit by the use of the TEG as described herein.
  • the TEG device 910 comprises a housing 920 that can be any acceptable shape and size. It includes a vent 922 and lower draft 924 in this embodiment.
  • the housing 920 is similar in shape and size to the housing 110 described above.
  • the internal mechanism, wiring and TEG (not shown), contained within the housing 920, are likewise, similar in size and function to those described above. In alternate embodiments, these components and their arrangement can differ, in part to accommodate the larger scale of the particular combustion chamber 910 shown in Fig. 9.
  • the heat-conducting probe 930 has been extended and shaped to overlie the charcoal fire 932 deposited on a supporting framework 934.
  • the airflow outlet 940 of the TEG device 910 lies approximately in line with the charcoal fire or bed.
  • a vented outlet pipe 942 is provided that extends beneath the coals 932 and delivers airflow (arrows 944) at predetermined locations within the chamber 902 so as to further oxidize the burning coals. It should be clear that this is only exemplary of a variety of geometries and placements for an air outlet according to the various embodiments herein. Likewise, vents within a pipe can be provided at a variety of locations that maximize airflow and minimize clogging.
  • a more complex outlet assembly can be provided and/or an outlet assembly that overlies the fire can be employed.
  • the outlet can be adapted to the size and shape of the particular combustion arrangement and provide to the end user based upon the particular arrangement.
  • the outlet assembly/pipe 942 can be removably attached to the housing 920 using clips, screws or other fasteners, or by another locking arrangement (not shown).
  • an insulating gasket 950 constructed from silicone or another insulating material is provided.
  • the TEG device 910 in this embodiment can be retrofitted to a preexisting kettle 902 or other single-walled enclosure by drilling a hole for each of the probe 930 and the pipe 942 through the wall thereof.
  • a mounting hook 960 is fastened by a fastener 962 to the wall (902) as shown). It engages a hook 970 mounted to the housing 920.
  • a large combustion device may be fitted with multiple TEG devices in accordance with the embodiments of this invention.
  • the kettle 902 can be provided with two or more TEG devices 910 positioned about its perimeter.
  • the TEG device is to be used with an open fire (a three-stone fire or barbeque pit, for example) it can be fitted with a removable and/or telescoping stand, hanging hook (or probe hook), leg assembly, or other support mechanisms.
  • Such a TEG device can also include an appropriately shaped and elongated probe and airflow distribution outlet (a nozzle arrangement for example), that best directs heat from and air to the burning fuel mass.
  • the term "wall" as used herein to describe a combustion chamber can refer to any barrier, such as an earthen base or stone that contains the fire. This term can in fact refer to a notional barrier, where the fire is formed as a pile of fuel with sufficient perimeter clearance to define a concentrated burning area without the fire spreading therebeyond.
  • the TEG device can be constructed so as to be remote from the wall and interconnected therewith via elongated probe and airflow outlet assemblies.
  • adjacent can be used to generally describe the location of the TEG either on or operatively connected, but remote from, the wall.
  • Fig. 10 details an embodiment that includes a variety of optional features, which can be applied variously to the embodiments described herein and are detailed in this view by way of further illustration.
  • the TEG device 1002 can be mounted on the wall 1012 of a single walled, side- feeding stove 1010, such as the depicted "rocket" stove arrangement.
  • the following description is also applicable to so-called gassifier designs that also allow for introduction of fuel via an elevated side drawer that contains the fuel.
  • the "rocket" design allows for elongated wood fuel 1014 to be manually directed through a side port 1016 that also acts as a vent for air/oxygen.
  • the fuel 1014 is advanced (arrow 1018) into the port 1016 along a crib 1020 as the leading end of the fuel combusts to ash.
  • the TEG device 1002 is mounted with respect to a bracket 1030 and/or through-cut that can include a side shield 1032, which prevents adjacent air warmed by the wall 1012 from directly entering the inlet 1034 of the TEG device 1002. This allows the inlet air passing over the TEG heat sink to be cooler, thereby enhancing the efficiency of the device.
  • the stove wall 1012 can include one or more ports (not shown) for accommodating one or more heat-conduction probes 1050 (shown in phantom projecting into the interior) as described generally herein.
  • the TEG device 1002 in this embodiment includes an air outlet port or pipe 1052 (shown in phantom also directed into the interior) that directs the airflow from the TEG device housing into the stove's interior/burn chamber.
  • the outlet pipe (or multiple pipes/outlets) can be oriented to provide a circulating and/or directional draft to the airflow.
  • the TEG device can alternately omit an outlet port in
  • the outlet port vents to ambient atmosphere.
  • the TEG device includes an electrical outlet 1070 that enables interconnection with a variety of electrical devices and/or the rechargeable battery circuits for such devices.
  • an electrical outlet 1070 that enables interconnection with a variety of electrical devices and/or the rechargeable battery circuits for such devices.
  • Two depicted examples are a light unit (for example a high- intensity solid state (LED) lamp) 1080 and a cellular telephone 1090.
  • a variety of other electronic and/or electrical devices can also be interconnected, including, but not limited to battery chargers, rechargeable power tools, laptop computers, PDAs, still and video cameras, navigation devices, radios, video players, signaling devices, and any other appliance that operates or allows charging within the limitations of the TEG device's generation capacity.
  • FIG. 11 an illustrative circuit arrangement 1 100 for the TEG device 1002 according to Fig. 10 is shown in further detail. Some or all of this schematic is also applicable to other embodiments herein, depending upon their respective requirements— for example whether or not the device includes batteries and/or cogeneration capabilities.
  • the circuit 1 100 includes the above-described TEG 1 110 in which the differential between heat on the hot side with respect to the cold side generates power that is directed to a motor control 1 112.
  • the motor control can be omitted in favor of a direct connection to the motor 11 14 that drives an airflow-driver (fan assembly) 1 116.
  • a plurality of motors and/or interconnected airflow drivers can be employed in alternate embodiments.
  • the TEG 1 110 (or another portion of the circuit) is operatively connected to a charging circuit 1 118 in this embodiment.
  • the charging circuit 1 118 provides charging current at an appropriate voltage level to the storage battery or capacitor 1120 as needed by the battery.
  • the battery 1120 is also connected via the motor control 1 1 12, or directly to the motor 1 1 14 to power it in the absence of sufficient TEG power.
  • the motor control can act as a balancing circuit between TEG and battery power in such instances.
  • the battery which discharges at a relatively level voltage and current, is connected to a power supply circuit 1 122 (typically of conventional design).
  • the power supply can include an optional potentiometer or digital voltage selector 1 124 that allows the output 1 126 to vary, so as to meet the specific voltage needs of the connected device.
  • One or more specific device connectors 1 130 can be provided.
  • the device connector 1 130 can consist of a cable with a conventional two-prong socket that mates to a variety of end connectors tailored to the specific device. Such an arrangement is currently commercially available in universal AD-to-DC converters.
  • the device connector 1130 can define a standard aircraft seat plug fitting and/or automotive cigar lighter socket residing on the device, adapted to connect to a commercially available 12 VDC male adapter that modifies the voltage (and current, where applicable) to meet the specific needs of the device.
  • a power adapter can be based upon the increasingly ubiquitous universal serial bus (USB) system. The implementation of such a USB-based power socket and power delivery system should be clear to those of skill in the art, and can be implemented either with or without the above-described battery.
  • circuit components including the storage battery/capacitor can be housed within an appropriately shaped and sized TEG device housing.
  • various components of the circuit can be housed separately and interconnected via fixed or detachable cabling and/or connectors.
  • the storage battery can be provided in a "piggyback" unit (not shown) that is removably attached to the main TEG device housing, and thereby completes an electrical connection between respective contact pads.
  • Figs. 12 and 13 depict a further embodiment of a cook stove 1200, adapted for side- feeding of fuel, implemented according to the principles described above.
  • This embodiment can be used in a family setting where (for example) utilities are unavailable.
  • the side- fed design allows for ease of fueling while a cooking utensil (pot, pan, etc.) is continually heated over an extended period of time.
  • the external shell 1210 of the device defines a conically shaped base that terminates at an outwardly tapering cooking top 1212.
  • This shell 1210 is designed in such a way as to provide a wide base for stability when cooking, and a wide cooking top surface to support a variety of cooking vessels.
  • the base and top can define the same width and/or diameter, and can range in size, for example, between 20 to 60 cm. Additionally, the height of the device can be approximately the same as the width for maximum stability and for to balance the proportions of the device. Alternatively, in other embodiments the height may be moderately smaller or larger than the width of the device. Further, in other embodiments the base and top need not be of the same width or diameter.
  • the width of the device is smaller in perimeter around its central waist region 1214, like an hourglass, to visually emphasize the cooking area and stable base, and to provide room for two opposing, side-mounted carrying handles 1216 (held in place by rivets, screws, welding, or the like) in a manner that is free of any increase in the overall perimeter of the stove 1200.
  • the relative size of the waist area with respect to the overall width of the device can be in a range of 20-50% of the overall width.
  • the outer shell can define an entirely different shape (e.g. a pot belly shape reminiscent of, for example, a beehive or tandori stove.
  • the cooking top 1212 can be formed from cast or stamped metal (e.g. aluminum, steel, etc.) and defines a bowl with a depressed open center having a central vent/chimney hole 1230.
  • a series of radially aligned raised standoffs 1220 act as supports for a pot or pan (not shown), and provide gaps between the base of such a pot/pan and the area between standoffs 1220 so that gas from the combustion is free to pass around the pot/pan between the standoffs and out into the surrounding air. As shown in the cross section of Fig.
  • the cooking top includes an outer, downwardly directed, tapered rim 1310 and in inner rim 1312, each constructed and arranged to removably engage top edges of the lower stove body, including the top edge of the upper portion 1320 of the outer shell 1210 and the upper region 1332 inner combustion chamber 1330.
  • the combustion chamber 1332 also includes a lower region 1334 that is formed with a separate set of walls 1336 that define a side entrance port 1338 and a passage 1340 into the upper region 1332.
  • the combustion chamber includes a floor 1342 above which is suspended a fuel crib 1230 that, in this embodiment passes partially into the lower region 1334 of the combustion chamber 1330.
  • the crib 1230 extends outwardly from the entrance port 1338 to allow fuel (typically in the form of biomass, such as elongated sticks of wood, or alternatively, peat, coals, etc.) to be supported thereon and slid into the combustion chamber as needed to maintain a fire.
  • the lower region 1334 includes a main combustion area beneath the upper region 1332 and a feed area defined by upper wall 1350 and side walls 1352.
  • the crib 1230 directs natural draft air both above and below the fuel for optimal combustion, and includes a radiant and convective heat deflector plate 1240 at the entrance to the fuel opening with a front-to rear (in the feed direction) length LC of approximately 2 to 10 cm, and spanning the width of the fuel opening.
  • the crib can be constructed from a welded lattice of stainless steel rod, or another heat-resistant material (e.g. a perforated stamped metal sheet or an iron casting).
  • the floor 1342 is provided on a base plate 1344 that is attached to the shell 1210 at a raised rim 1346 that maintains the base plate off of the ground by several centimeters, thereby avoiding direct contact of the hot base with the ground.
  • the rim is continuous and solid to maximize thermal efficiency by trapping hot air under the device.
  • vent holes (1347) or slots/gaps can be included to allow the escape of moisture.
  • a portion 1348 of the base plate 1344 is angled downwardly toward the fuel entrance port 1338. This allows for drainage of any
  • the combustion gasses and associated flame generated by burning of fuel in the lower region 1334 of the combustion chamber 1330 are directed upwardly and pass into the upper region 1332.
  • multiple air-injection ports around the top (ports 1360) and at locations along the middle (port 1362) and bottom (port 1364) of the upper region 1332 are employed to effectively distribute the air inside the overall combustion area for improved mixing and cleaner combustion.
  • the upper ports define rows that perforate the wall of the combustion chamber at regular spacing about the chamber. In this embodiment, the ports of the upper row are spaced at a greater distance than the lower row.
  • the middle and bottom ports 1362 and 1364 are located at approximately 90 degree offsets about the circumference in this embodiment.
  • the ports 1360, 1362, and 1364 are circular as shown, but other perimeter shapes are expressly contemplated. Additionally, the ports are between approximately of 2mm to 10mm in diameter, depending in part upon the overall size of the stove and associated combustion chamber. The total number of ports can vary from approximately 2 to 50 depending in part upon the size of the ports, where a larger number of ports is typically employed for smaller diameters, and vice-versa.
  • the TEG assembly 1250 is shown mounted (removably mounted in various optional arrangements) on the exterior of the stove body.
  • a cutout in the outer shell 1210 facilitates positioning of the TEG assembly 1250 adjacent to (and confronting) the upper region 1332 of the combustion chamber 1330.
  • the TEG assembly 1250 includes an outer housing shell 1372 that allows ambient (outside) air to enter through vents as described above.
  • the air is driven by the fan assembly 1372 (more generally termed an "airflow driver"), which is powered by the TEG 1373, which is connected to an associated heat sink 1374 connected to the "cold" side of the TEG. Airflow passes over the heat sink 1374 to create the desired temperature differential across the TEG as described above.
  • the "hot" side of the TEG 1373 is interconnected to a temperature probe assembly 1376 that engages the TEG over a wide area and tapers into a relatively small cross-sectional diameter/perimeter shaft 1378 extending approximately to a center line of the upper region 1332 of the combustion chamber 1330.
  • the probe shaft can be solid or a hollow tube in various embodiments.
  • the probe is located approximately one third of the vertical distance from the bottom of the upper region 1332 in this embodiment. Probe placement is variable in other embodiments and can be located in a region that contains an optimal average concentration of heat energy.
  • the fan assembly 1372 drives airflow into an intermediate space 1380 defined between the inner wall 1382 of the upper region 1332 and an outer wall 1384 via appropriate ports that connect the TEG assembly 1250 to the outer wall 1384.
  • the air directed into the space is distributed into the upper region 1332 of the combustion chamber 1330 via ports 1360, 1362 and 1364 so as to enhance combustion as described above.
  • a higher-temperature, lower-smoke combustion product results based upon the injected airflow.
  • the TEG assembly 1250 can include appropriate circuitry (described generally above and enclosed in the housing shell 1370) to operate a system of electrical power storage and/or distribution via, for example, a 12 VDC outlet and/or one or more USB-compatible sockets that are powered by the appropriate voltage.
  • appropriate circuitry described generally above and enclosed in the housing shell 1370 to operate a system of electrical power storage and/or distribution via, for example, a 12 VDC outlet and/or one or more USB-compatible sockets that are powered by the appropriate voltage.
  • the term “smoke-free” or “waste-free” is intended to mean that the device operates by burning a fuel while producing very little to no smoke as it burns the fuel.
  • the term “TEG” as used herein should be taken broadly to refer to a variety of equivalent devices that are capable of converting heat from a source into electrical energy in a manner that can be used in accordance with the general arrangement of components described and contemplated in accordance with this invention.
  • the TEG device can comprise an array of devices, each in communication with a portion of the heat source/flame where appropriate.
  • the combustion device as described herein has been largely cylindrical in shape with a generally circular perimeter, particularly the combustion chamber and heat shield. However, its perimeter may define any cross-sectional shape including square, rectangular, triangular, and the like.
  • the stove or other combustion arrangement can be constructed and arranged to receive initial and/or replacement fuel from any position, including, but not limited to bottom- feed, top-feed and side-feed.
  • the cross-sectional shape of the probe is generally circular (cylindrical), the cross section can vary.
  • the cross section shape can be rectangular, polygonal, ovular or irregular. More generally, any structure that acts as a heat-transfer conduit from the heat source/flame to the TEG can be considered a "probe" in accordance with this invention. Likewise, the cross section shape and/or size can vary along the length of the probe (e.g. a taper).
  • the airflow driver in the depicted embodiments is generally a fan, such as an impeller, the energy can be used to store air pressure (using a compressor and storage tank), for release at appropriate times (and in appropriate volume) via a valve and conduit.
  • the airflow driver can comprise a compressor or suction pump that draws air at a desired rate.
  • any device that generates desired airflow can be considered an airflow driver for the purposes of this description.
  • the standoff (108) of the illustrative combustion device is depicted as comprising a plurality of metal segments welded together to form a surface for receiving an item such as a skillet or other device for heating food or any other substance desired to be heated
  • any appropriate supporting structure may be employed for placing an item atop the combustion chamber so that it may be heated, such as a skillet for cooking food.
  • the upper region of the combustion chamber is shown as a cylinder, it can be a tapered structure and/or define any regular (e.g. polygonal) or irregular cross-sectional shape. Accordingly, this description is meant to be taken only by way of example, and not to otherwise limit the scope of this invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Solid-Fuel Combustion (AREA)

Abstract

L'invention porte sur un dispositif de combustion portable qui fournit une combustion plus propre, qui réduit la période d'allumage et qui permet d'obtenir une combustion globale de meilleur rendement par l'utilisation d'un ventilateur qui dirige un volume prédéterminé d'écoulement d'air sur le carburant combustible - typiquement du bois ou des solides biologiques à base de cellulose similaires. Le dispositif de combustion possède une chambre de combustion comportant une source de carburant. Un boîtier renferme le générateur thermoélectrique sur le côté du dispositif, celui-ci générant une sortie électrique sur la base d'un différentiel de température entre les côtés opposés du générateur thermoélectrique. Une sonde conduisant la chaleur est montée sur le générateur thermoélectrique et fait saillie dans la chambre de combustion. Le côté opposé du générateur thermoélectrique vient en contact avec un dissipateur de chaleur qui entre en interaction avec l'air ambiant. Un ventilateur aspire l'air chauffé de façon à l'éloigner du dissipateur de chaleur, et force l'air sur le carburant de combustion à travers une pluralité d'orifices périphériques qui sont reliés à un espace d'air situé entre des parois interne et externe de la chambre de combustion.
PCT/US2013/067284 2012-10-29 2013-10-29 Dispositif de combustion portable utilisant une génération thermoélectrique WO2014070754A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US13/662,650 2012-10-29
US13/662,650 US8851062B2 (en) 2008-10-07 2012-10-29 Portable combustion device utilizing thermoelectrical generation

Publications (1)

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WO2014070754A1 true WO2014070754A1 (fr) 2014-05-08

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Publication number Priority date Publication date Assignee Title
CN105371304A (zh) * 2014-08-26 2016-03-02 李崇杰 一种蒸煮采暖多用途生物质燃烧炉
GB2551040A (en) * 2017-05-10 2017-12-06 Valiant Stoves Ltd Flue-Pipe Fan
CN109163362A (zh) * 2018-07-24 2019-01-08 珠海格力电器股份有限公司 燃烧装置及聚能圈
CN110657590A (zh) * 2019-09-30 2020-01-07 中国人民解放军32181部队 一种温差发电炉
WO2021077147A1 (fr) * 2019-10-24 2021-04-29 Smart Pellet Heater Gmbh Dispositif pour brûler des combustibles solides en extérieur
CN114076325A (zh) * 2020-08-21 2022-02-22 宁波方太厨具有限公司 余热利用装置及包含其的灶具

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US6019098A (en) * 1993-10-19 2000-02-01 Hi-Z Technology, Inc. Self powered furnace
US6588419B1 (en) * 2002-06-10 2003-07-08 Honeywell International Inc. Fireplace insert thermally generating electrical power useful for operating a circulating fan
JP2004156811A (ja) * 2002-11-05 2004-06-03 Idemitsu Kosan Co Ltd 燃焼暖房装置
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US6019098A (en) * 1993-10-19 2000-02-01 Hi-Z Technology, Inc. Self powered furnace
US6588419B1 (en) * 2002-06-10 2003-07-08 Honeywell International Inc. Fireplace insert thermally generating electrical power useful for operating a circulating fan
JP2004156811A (ja) * 2002-11-05 2004-06-03 Idemitsu Kosan Co Ltd 燃焼暖房装置
US20090025730A1 (en) * 2007-07-24 2009-01-29 Pinel Lloyd J Post decannulation stoma cover
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105371304A (zh) * 2014-08-26 2016-03-02 李崇杰 一种蒸煮采暖多用途生物质燃烧炉
CN105371304B (zh) * 2014-08-26 2018-07-17 李崇杰 一种蒸煮采暖多用途生物质燃烧炉
GB2551040A (en) * 2017-05-10 2017-12-06 Valiant Stoves Ltd Flue-Pipe Fan
GB2551040B (en) * 2017-05-10 2018-06-20 Valiant Stoves Ltd Flue-Pipe Fan
CN109163362A (zh) * 2018-07-24 2019-01-08 珠海格力电器股份有限公司 燃烧装置及聚能圈
CN110657590A (zh) * 2019-09-30 2020-01-07 中国人民解放军32181部队 一种温差发电炉
WO2021077147A1 (fr) * 2019-10-24 2021-04-29 Smart Pellet Heater Gmbh Dispositif pour brûler des combustibles solides en extérieur
CN114076325A (zh) * 2020-08-21 2022-02-22 宁波方太厨具有限公司 余热利用装置及包含其的灶具

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